Method fob conveying concrete aggregate



H. 0. STAMP.

METHOD FOR CONVEYING CONCRETE AGGREGATE. l

APPLICATION FILED FEB. 8. 19m

1,304,619. Patented May 27, 1919.

HUGO O. STAMP, OF MILWAUKEE, WISCONSIN.

METHOD FOR CONVEYING CONCRETE AGGREGATE.

Specification of Letters Patent. Patented May 2'7, 1919.

Application filed February 8, 1917. Serial No. 147,285.

- of Milwaukee, in the county of Milwaukee and State of Wisconsin, haveinvented certain new and useful Improvements m- Methods for ConveyingConcrete Aggregate; and I do hereby declare that the following is afull,clear, and exact description thereof.

Myinvention relates to new and useful improvements in means forconveying concrete aggregate to a mixing machine from storage pilesalong the roadway.

In view of the temporary nature of general concrete conveyingoperations, it is desirable to provide a means for conveying involvingan apparatus which is cheap and easily portable.

Concrete aggregate usually comprises different ingredients and theseingredients must be delivered in successive batches to the concretemixer in definite relative proportions.

A further consideration is the relatively large volume of aggregatenecessarily stored under practical conditions adjacent the mixer, themixing capacity of which in many instances amounts to a cubic yard ofsand and gravelper minute.

It is primarily the object of my invention to provide a method forconveying concrete aggregate in a manner adv antageously meeting all ofthe aforementioned considerations.

It is more particularly an object of my invention to provide a method ofconveying concrete aggregate involving the conveying movement of theaggregate by a single conveyer conveying both materials continually,thereby permitting a minimum storage space between the several stepsafter the materials leave the ground storage piles and thereby allowinga construction of minimum height to pass under trolley wires, tunnels,etc., Without dismantling.

Figure 1 illustrates diagrammatically one form of apparatus adapted forcarrying out my improved method of conveying concrete aggregate.

Fig. 2 is a plan view of the horizontal conveyer portion of saidapparatus, showing the relative disposition of aggregate ingredientsthere adjacent.

Referring now more particularly to thedrawing, '5 designates thereceiving portlon of a concrete mixer, and arranged to dischargethereinto ar .pair of measuring hoppers 6 and 7 respeiitively,controlled by suitable valves 8 in their bottom, and these hoppers areof a relative capacity corresponding to the desired proportion of sandand gravel to be discharged into the mixer, nd said hoppers may bevariable in capacity f deslred to vary the proportion. Disposed aboveand adapted to discharge into the measuring hoppers 6 and 7 are a pairof storage bins 9 and 10 respectively, having outlet valves 11 anddisposedthereabove is an inclined screen 12 suspended by pivoted hangerarms 13 and connected with an oscillatory pitman 14 mountedeccentrically on a suitable driven wheel 15. As shown, the screen isdlsposed over t e bin 10, whereby material passing through its mesh willfall thereinto, and the lower end of the screen is dis osed adjacent oneedge of the bin 10 where y material passing over the screen Willdischarge into said bin 9. For conveying concrete aggregate to thescreen, an elevator 16 is arranged to discharge thereonto and has a boot17 at its lower end for receiving the discharge of a horizontal conveyer18 which extends a considerable distance along the ground and adapted tolie between plles of aggregate ingredients. along the road-way.

In carrying out my improved method it should be understood that it isadapted to economically handle the several finished products which maybe termed aggregate, and, as described, the several finished prod nets,in this instance sand and gravel, are storedon the ground inindiscriminate piles along lines paralleling the conveyer 18,-the groundpiles of the congregated mass are then fed to the conveyer in 'acontinuous stream and in roughly proportionate quantities more or lessmixed and from this conveyer they are raised to the desired height by anelevator 16. After reaching this elevation the mass-Will then flow bygravity through several steps of the process to the mixer. It is firstdischarged upon the oscillating screen 12,-whereby the sand and gravelare separated and caused to flow in'individual streams to equalizingbins 9 and 10 which serve as momentary dams for each finished product.Thus the bins9 and 10 serve to compensate for temporary varia tions, inrelative amounts of differing ingredients fed to the conveyer 18 and tosaid bins by the conveyer. From these bins the separated finishedproducts are released and flow into hoppers 6 and 7 Where they are heldin suspension and measured. Thereafter the measured finished productsare released and caused to flow together coincident to their dischargeinto the mixer proper. By thus conveying the two materials in a stream,which is practically a continuous process, large quantities of materialmay be moved with only a single conveyer and the bins 9 and 10 need beof only sufiicient capacity to compensate for any temporary variation inthe supply of their respective materials thereto by depositing saidrespective materials in roughly proportionate quantities on the conveyer1 8 and also to provide a means for holding the materials while themeasuring bins 6 and 7 are discharging. Thus they act only as reservoirsof small capacity to provide the necessary continuity of operation whenchanging from the continuous process of conveying to the intermittentprocess of feeding the measured batches into the mixer, and not as binsfor storing the material, since the storage of the large amounts ofmaterial to permit uninterrupted operation of the job as a whole,despite stoppage of the source of supply, is performed by the groundpiles adjacent the conveyer, which in practice consists of many hundredsof cubic yards of sand and stone while the capacity of the storagehoppers 9-and 10 would be only a yard or two.

By this method of conveying, the storage hoppers can be reduced to acapacity which is less than the amount of material contained in thescreen, elevator and conveyer combined and therefore since the height ofa machine will be proportional to the capacity of this hopper, it willbe seen that this is the reason a structure of a height not to exceedthat permitting its passing under tunnels, trolley wires, etc, can beused. Concrete aggregate usually comprises diifering ingredientscomposed of particles of considerably differing size, such as sand andgravel or stone. The usual size of the particles of sand is such aswould pass of the particles of each aggregate ingredient.

By my improved method of conveying, a considerable economy of structureis procured inasmuch as the conveying means may be operated and fedcontinuously, and also, my improved method eliminates the duplication ofstructure involved in the provision of two conveyers, and a furthereconomy in this respect is effected by the fact that the mixture of thesand and gravel will occupy a bulk considerably less than the sum oftheir bulks when separated, due to the disposition of the sand into theinterstices of the mass of gravel. Thus a relatively small size of thesingle conveyer may be had. This economy of structure permits a plant ofsuitable capacity to be kept within the weight limit necessary forportability.

What is claimed is:

The method of conveying, proportioning and feeding the ingredients ofaggregate material, said method consisting in depositing upon a commonprimary conveyer from storage piles of said ingredients, roughlyproportionate quantities of said ingredients, conveying and elevatingsaid ingredients, separating said ingredients from each other,temporarily separately accumulating each of said ingredients and finallyfeeding from said accumulations exact proportional quantities of thesaid ingredients deposited upon said primary conveyer. v

In testimony that I claim the foregoing I have hereunto set my hand atMilwaukee, in the county of Milwaukee and State of Wisconsin, in thepresence of twowitnesses.

mice 0. STAMP Witnesses:

FRANK L. RATOLIFFE, MAY .DOWNEY.

